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A method for pretreatment of molten iron desiliconization, dephosphorization, desulfurization and demanganization

A technology for pretreatment and molten iron, which is applied in the fields of dephosphorization, desulfurization, desiliconization of molten iron, and demanganese pretreatment, which can solve the problem that desiliconization and dephosphorization cannot be completed simultaneously.

Active Publication Date: 2019-10-18
XINGTAI IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example, desulphurization often adopts the method of spraying magnesium particles and KR stirring method, but these methods have a characteristic, that is, the simultaneous completion of desiliconization and dephosphorization cannot be achieved at the same time as desulfurization. De-siliconization, dephosphorization, desulfurization, and demanganization of molten iron is not yet a perfect pretreatment method for molten iron.
[0004] The invention introduces an AOD converter to solve the problem of simultaneous desiliconization, dephosphorization, desulfurization and demanganization of molten iron, and provides a new process and new idea for reducing production costs and smelting high-quality steel

Method used

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  • A method for pretreatment of molten iron desiliconization, dephosphorization, desulfurization and demanganization
  • A method for pretreatment of molten iron desiliconization, dephosphorization, desulfurization and demanganization
  • A method for pretreatment of molten iron desiliconization, dephosphorization, desulfurization and demanganization

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Experimental program
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Effect test

Embodiment 1

[0020] This embodiment focuses on desulfurization during the fourth stripping of molten iron, see Table 1 for details.

[0021] Table 1

[0022]

[0023] The specific calculation process is as follows:

[0024] The temperature of molten iron is 1250°C, the [Si] content is 0.426%, and the weight is 45.4 tons.

[0025] a. Oxygen is blown in until [Si] is fully oxidized and the exothermic temperature rises to 0.426×350=149°C; the oxygen consumption is 45.4×1000×0.426%×0.8=154.7m³;

[0026] b. The amount of lime added (the value of alkalinity is 1.5, the value of lime effective calcium oxide is 90%)=45.4×1000×0.426%×2.14×1.5 / 0.9=689.8kg, lime cooling=30×0.6898=20.7℃;

[0027] c. Amount of oxide scale added (12kg per ton of iron): 45.4×12=545.2kg; cooling down of oxide scale: 0.542×120=65.4;

[0028] d. The calculated temperature of the molten pool is: initial temperature + silicon element oxidation exotherm - lime cooling - oxide scale cooling = 1250+149-20.7-65.4 =1312.9°C;...

Embodiment 2

[0037] In this embodiment, the operations of dephosphorization and manganese removal are strengthened at the same time as the fourth removal of molten iron, see Table 2 for details.

[0038] Table 2

[0039]

[0040] The specific calculation process is as follows:

[0041] The temperature of molten iron is 1250°C, the content of [Si] is 0.44%, and the weight is 45.3 tons.

[0042] a. Oxygen is blown in until [Si] is fully oxidized and the exothermic temperature rises to 0.44×350=154°C; oxygen consumption is 45.3×1000×0.44%×0.8=159.5m³;

[0043] b. The amount of lime added (the value of alkalinity is 1.5, and the value of lime effective calcium oxide is 90%)=45.3×1000×0.44%×2.14×1.5 / 0.9= 711kg, lime cooling=30×0.711=21.3℃;

[0044] c. The amount of iron oxide scale added (the value is 22.5kg per ton of iron)=45.3×22.5=1008 kg; the temperature reduction of iron oxide scale=120×1.008=121°C;

[0045] d. The calculated temperature of the molten pool is: initial temperature + ...

Embodiment 3

[0054] In this embodiment, desulphurization is abandoned, and desiliconization, dephosphorization, and manganese removal are realized. The furnace number is 130000188 furnace times. See Table 3 for details.

[0055] table 3

[0056]

[0057] The specific calculation process is as follows:

[0058] The temperature of molten iron is 1250°C, the content of [Si] is 0.38%, and the weight is 44.6 tons.

[0059] a. Oxygen is blown in until [Si] is fully oxidized and the exothermic temperature rises to 0.38×350=133°C; oxygen consumption is 44.6×1000×0.38%×0.8=135.6m³;

[0060] b. The amount of lime added (due to abandoning desulfurization, single slag is used, the value of alkalinity is 2.5, and the value of lime effective calcium oxide is 90%)=44.6×1000×0.38%×2.14×2.5 / 0.9=1007kg, lime cooling=30 ×1.007=30.2℃;

[0061] c. Addition amount of iron oxide scale (23kg per ton of iron)=44.6×23=1026kg; cooling of iron oxide scale=120×1.026=123.1 ℃;

[0062] d. The calculated temperature...

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Abstract

The invention discloses a method for desilication, dephosphorization, desulfuration and demanganizing pretreatment of molten iron. By employing the mechanism of removing silicon, manganese, phosphorusand sulfur through reactions in the steel-making process, the requirements of desilication, dephosphorization, desulfuration and demanganizing on the molten iron at the same time are realized by adding appropriate amounts of process materials, and controlling appropriate temperatures and oxygen and nitrogen contents. The requirements of special steel on molten iron pretreatment are met, the pretreatment effects that terminal Si is less than or equal to 0.15%, the desulphurization rate is greater than or equal to 90%, the dephosphorization rate is 30-70% and the demanganizing rate is 40-80% are achieved, and by adjusting processing parameters, the higher removing effect of a certain element can be obtained; the smelting cost of per ton of iron is less than or equal to 70 RMB / ton, and the time of the entire AOD treatment process is less than or equal to 25 min; and the molten iron desilication, dephosphorization, desulfuration and the demanganizing requirements can be realized rapidly without investing or constructing various pretreatment facilities, the new requirements of special steel on molten iron pretreatment are met, and the former special steel which cannot be produced due to the limitation of one or more of Si, Mn, P and S can be produced possibly.

Description

technical field [0001] The invention belongs to the technical field of iron and steel smelting, and in particular relates to a pretreatment method for desiliconization, dephosphorization, desulfurization and demanganization of molten iron. Background technique [0002] In order to meet the requirements of smelting high-quality steel, various factories have more and more stringent requirements on the quality of molten iron smelted in converters. In many cases, three removals (desiliconization, dephosphorization, and desulfurization) of molten iron are required. With the continuous improvement of product quality requirements, some steel grades even have a demand for "removal of manganese". [0003] As we all know, in order to achieve a requirement of molten iron pretreatment, separate equipment and methods are required. For example, desulphurization often adopts the method of spraying magnesium particles and KR stirring method, but these methods have a characteristic, that i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C1/02C21C1/04
Inventor 曹红波王郢郭键韩清连吴广海冯文甫雷学东郭志彬李智王晓亮
Owner XINGTAI IRON & STEEL